Application of computers to engine control is well understood. In order to operate properly, engines need different amounts of fuel based on their temperature, atmospheric temperature, atmospheric pressure, RPM etc. for a given throttle setting. Application of various sensors is used to meter and regulate fuel flow and air mass to achieve stoicheimetric combustion. The primary purpose is to achieve high fuel average efficiency and minimize combustion byproducts. A comprehensive description of the prior art is found in U.S. Pat. No. 6,016,794(2000) to Hasimoto et al. incorporated herein by reference.
The present invention herein named the ECM is a computer commanded device that measures engine parameters and calculates how much fuel the engine should receive, then it supplies that amount of fuel by opening fuel injectors for a calculated length of time. These fuel injectors are opened so that the fuel is injected into the intake manifold and hence the engine piston cylinders at the proper time. Once the fuel has been delivered, spark plug firing is executed at user specified angles during each combustion cycle (may not be used in diesel application). The ECM maximizes engine performance by setting the firing angle based on the currently measured RPM value. The ECM is housed in a small box attached to the vehicle. The box contains a computer with its program and many parameters that control how it operates saved in a non-volatile FLASH memory device. The ECM has a connector that attaches to a wiring harness that is wired to the necessary places in the engine where the thermistors, transducers, ignition coils and fuel injectors reside, as well as an RS-232 serial port.
A key feature of the present invention is a communications link from the ECM to a remote computer running custom developed software. This software allows the operator to observe and change all of the operating parameters for the ECM. In this manner, the operation of the ECM can be optimized for the engine it is controlling and can be customized for the particular engine and driver of the vehicle.
Prior art engine control systems fixed sensor calibration, linearization and gross approximation to fuel requirements over various engine speeds. Prior art controls are designed for “good” performance within the variability of various sensor and transducer error, aging of the controller electronics, variation of mechanical and dimensioned surface finishes. In addition the prior art controller must perform over the life of the product which could be 200,000 miles, wherein wear of fuel injector parts, timing chains, and other parts cause a drift away from initial operating parameters. Serious constraints are put on the prior art engine performance. The non-programmable prior art requires the performance to be fixed for “minimal average” to work within sensor and engine variation.
The user may over the life of the engine change components such as injectors, manifold, and engine displacement. The engine with the “stock” controller may run poorly as a result. Without access to alter critical engine parameters the full benefit of installing “high performance” components to prior art controllers is not realized. The instant invention allows the user or technician to optimize all critical parameters over the life of the engine. It also allows the addition or changing of sensors, thermistors, and transducers. Access to real-time engine parameters and historical data not available in the prior art.